The present invention relates generally to riding toys for children and more particularly to riding toys of the power driven variety as opposed to such toys which are self-propelled as by pedals and the like. More particularly, the present invention relates to improvements in control circuitry for such toys which are powered by rechargable storage batteries which drive dedicated direct current motors coupled to the wheels of such a toy.
Storage battery powered childrens toys including such toys which are sufficiently large to allow the child to ride in or on the toy are well known. Such toys sometimes include foot operated power switches for connecting drive motors to the battery power source and sometimes include forward-reverse switches which the child may actuate for the purpose of backing the toy rather than moving it in its normal forward direction.
Mechanical braking arrangements for childrens toys are also well known but are not commonly encountered on battery powered riding toys either because of the expense of such mechanical braking systems or the thought that such toys move at sufficiently slow speeds that no braking arrangement is necessary. Another reason for the absence of braking arrangements on small battery powered riding toys may be that the complexity of the controls would be so confusing to the child as to render them useless or undesirable.
While not having found any significant market in the area of childrens' riding toys, so called dynamic braking of electric motor powered devices is a relatively old and well developed technique. This technique has been employed in elevators and street cars and simply stated such dynamic braking amounts to a disconnecting of the electric drive motor from its power source and a shorting or shunting of the motor input leads by a comparatively small resistance so that as the object continues to turn or move, the motor is now operating as a generator into the shunting resistance and this resistance acts like a load on the generator impeding its continued rotation. Illustrative of such a dynamic braking scheme is the arrangement illustrated in an electric car, disclosed in U.S. Pat. No. 4,313,517.
In this patented arrangement, in addition to mechanical braking, the drive motor of a permanent magnet series wound type may selectively be short circuited by closure of a solenoid operated switch so that the motor acts as a generator with a load formed as the series combination of that closed switch and a resistance so as to apply a dynamic braking force to the wheel or wheels driven by that motor. The comparatively complex circuit arrangement for controlling this electric car is illustrated in FIG. 19 of the patent. The control complexity as well as the expense of such an arrangement renders it totally unsuitable for a child's toy.